daemon: Add --log-target=journal to pulseaudio.service

When running under systemd from its .service file, the daemon is started with --daemonize=no. This means that the default logging target is stderr (see the documentation for --log-target in pulse-daemon.conf(5)). That works fine, but results in all the structured logging data from the pa_log() calls being thrown away and not making it into the journal.

In order to preserve structured logging data, and hence make the messages in the journal a little more useful (for example, allowing the user to filter by message priority), explicitly pass --log-target=journal in the .service file. This should always be appropriate because the journal should always be used with systemd.

Signed-off-by: Philip Withnall withnall@endlessm.com